Originally published in Geo Outlook magazine, 2010 Vol 7. No. 2
Written by Sara Stephenson
Ecotope, of Seattle, Wash., handled mechanical engineering. Bob Davis, the mechanical engineer, chose a geothermal system with the hope of gaining LEED® certification. Davis says the project is aiming for a platinum rating, the highest Leadership in Energy and Environmental Design certification.
Sixty-eight ClimateMaster units provide the hotel and its guests with the utmost comfort for its heating and cooling needs. The GSHP system ensures energy efficient heating and cooling in all the guest rooms, the spa and the domestic hot water supply.
“It’s one of their main advantages,” Pometta said.
Planner and eco developer for the project, Phil Sherburne, set his goal to create a completely sustainable resort. With the help of a professional team of architects and contractors, Sherburne achieved that goal.
“They’re going for every sustainable option,” Pometta said. Motion sensors were placed in each 540-square-foot room to monitor the guest’s activity. These sensors automatically turn off all electricity in the room, drop the shades and adjust temperature settings when the guest leaves, and the original settings are reset when the guest returns to the room. The shades are designed to shut automatically as a means of keeping the room cool and to rise to let in the sun and warm the room. This keeps the geothermal heating and cooling system from turning on before necessary and saves energy.
Other sustainable features of the hotel include photovoltaic electric generation, a preheat option on the water heater from the geothermal system and use of all sustainable forestry, Pometta said.
Measures were also taken to reduce the amount of electrical energy needed in the hotel. A large amount of glass was used in the design of the hotel to reduce the need for electrical lighting during the day, according to the Bardessono Web site. All lights used throughout the hotel are LED, halogen or fluorescent bulbs.
Ken Brew of Bertram Drilling, Inc., in Billings, Mont., was in charge of drilling the bore holes for the GSHP system and putting the loop in the ground. He completed the drilling
for the project September 2007. The bore field, consisting of 72 bores at 300 feet deep, was drilled on the west side of the building, Brew said.
Brew has been working with geothermal systems since 1989 and said this project was pretty standard as far as the drilling goes. “It was a pretty good job,” he said. “There were no hurdles we had to climb over.”
The forced air, water-to-water system circulates water through the 1-inch, 610-foot uni-coils of high-density polyethylene piping in the vertical system, said Mark Morelli of Air Connection Inc., in Santa Rosa, Calif. No other fluid besides water was used in this system.
“It’s not a place where we have to use anti-freeze,” Morelli said. “The majority of our focus was on the ground loop,” Morelli said. “Our role was to provide and install the geothermal loop.” Morelli has worked on several geothermal projects that equate to about 30 installations and roughly 500 bore holes.
The Bardessono wells needed to be drilled 300 feet into the ground where the ambient ground temperature remains a constant 70 degrees throughout the year, which is higher than most regions where the ambient ground temperature is a constant 55 degrees, Pometta said. The biggest challenge on this project was not systematic but geographic, he said.
“Napa Valley is a geographically active area, which makes the ground warmer than usual,” Pometta said.
A vault was also installed on the property to house control valves for the individual units. This way, each unit can be controlled separately through the circuits. There are a total of eight circuits and each circuit controls nine bore holes, Morelli said.
Installing the system came to a total cost of about $450,000 and was completed February 2008, Morelli said. Construction on the project began in December 2006.
Developers were interested in making the construction process as eco-friendly as the completed project. “The goal was to keep the site very clean and we were able to keep it free of mud and debris,” Morelli said. “Coordination with the project went really smoothly.”
Cello and Maudru Construction Company in Napa Valley, Calif., was the general contractor for the project. They created a system to recycle and reuse waste from the construction site. With this system in place, the company was able to recycle more than 93 percent of all waste created during the construction process, according to the Bardessono Web site.
An Example of Green Luxury
From start to finish, the Bardessono resort was created as an example of luxury and sustainability in both planning and building. The resort offers guests an opportunity to relax, enjoy the wine country of Napa Valley. Guests also gain peace-of-mind, from knowing every part of the Bardessono is friendly to the environment.
“At 600 bucks a night, that’s a good deal,” Pometta said.